The referenced, earlier application 06/677,171, filed Dec. 3, 1984, describes a longitudinal folding apparatus for use with rotary printing machines having a folding triangle or folding former, feed or supply rollers to which a plurality of superposed webs, for example paper webs delivered from a rotary printing machine, are supplied. Printing machines, as ist customary, print on, and hence supply unperforated webs. To provide for accurate placement of the paper webs above each other, for example upon folding, the supply rollers and/or the pull-off rollers have engagement projections extending therefrom, for example pins, which are dimensioned to pass the various superposed webs, so that registry of the respective webs is maintained. These pins may be pointed needles and when assembled on a roller, the roller may be termed a "prickly roller".
It has been found that it is difficult to thread a folding arrangement of this type since the projections, particularly if in the form of needle-like pins, interfere with threading of the webs through the apparatus before it is actually placed in operation.